<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>

  <body>
    <div id="app"></div>

    <template id="my-app">
      <h2>{{counter}}</h2>
      <!-- v-once：用于元素或组件只渲染一次 -->
      <div v-once>
        <h2>{{counter}}</h2>
        <h2>{{message}}</h2>
      </div>
      <button @click="counter++">按钮</button>
    </template>

    <script src="../js/Vue.js"></script>
    <script>
      const app = {
        template: '#my-app',
        data() {
          return {
            message: 'Hello World',
            counter: 100
          }
        }
      }

      Vue.createApp(app).mount('#app')
    </script>
  </body>
</html>
